Hi there. I think its ethical to keep treating her as long as she is responsive. I do hope she is in a tank of at least 5 gallons, if not you could put her in one, with heat, light, a filter and some live plants. Sometimes it takes fish a long time to die, sorry to put it that way.I once had a goldfish that I hand fed with a syringe for a year, then he died anyway.We do what we can with what we have, you very kind to help her. Bettas are pretty hardy fish, she may just make it. She is amazing, sick as she is, to watch your kids and the cat. I have found Bettas to be very intelligent with cool personalities. I hope you are rewarded with a healthy fish.